Patent US5298784A successfully refreshed from Google Patents.
US5298784A
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Electrically programmable antifuse using metal penetration of a junction
Assignee: International Business Machines Corp
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Filing: 1992-03-27
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Granted: 1994-03-29
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Expires: 2012-03-27
Abstract
Abstract An improved antifuse uses metal penetration of either a P-N diode junction or a Schottky diode. The P-N junction, or Schottky diode, is contacted by a diffusion barrier such as TiN, W, Ti-W alloy, or layers of Ti and Cr, with a metal such as Al. Al-CU alloy, Cu, Au, or Ag on top of the diffusion barrier. When this junction is stressed with voltage pulse producing a high current density, severe joule heating occurs resulting in metal penetration of the diffusion barrier and the junction. The voltage drop across the junction decreases by about a factor of ten after the current stress and is stable thereafter. Alternatively, a shallow P-N junction in a silicon substrate is contacted by a layer of metal that forms a silicide, such as Ti, Cr, W, Mo, or Ta. Stressing the junction with a voltage pulse to produce a high current density results in the metal penetrating the junction and reacting with the substrate to form a silicide.
Inventors
- 👤 Jeffrey P. Gambino
- 👤 Dominic J. Schepis
- 👤 Krishna Seshan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:29
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/493; H10W20/491
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
109 words
An electrically programmable antifuse comprising: a silicon substrate; a diode P-N junction formed in said silicon substrate; isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; a metal diffusion barrier over said P-N junction; a metal layer over said diffusion barrier; and programmable pulse generating means connected across said metal layer and said silicon substrate for stressing said P-N junction by a voltage pulse to produce a prescribed current density and creating a prescribed joule heating resulting in metal layer penetration into said P-N junction to thereby program said antifuse to conduct at prescribed voltages.
Claim 2
Dependent Claim
109 words
An electrically programmable antifuse comprising: a silicon substrate; a diode P-N junction formed in said silicon substrate; isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; a metal diffusion barrier over said P-N junction; a metal layer over said diffusion barrier; and programmable pulse generating means connected across said metal layer and said silicon substrate for stressing said P-N junction by a voltage pulse to produce a prescribed current density and creating a prescribed joule heating resulting in metal layer penetration into said P-N junction to thereby program said antifuse to conduct at prescribed voltages.
Claim 3
Dependent Claim
26 words
The antifuse recited in claim 1 wherein said isolation means comprises a trench in said substrate surrounding said P-N junction and filled with SiO 2 .
Claim 4
Dependent Claim
49 words
The antifuse recited in claim 2 wherein said diffusion barrier is selected from the group consisting of TiN, W, Ti-W alloy, and layers of Ti and Cr, and said metal layer is composed of a metal selected from the group consisting of Al, Al-Cu alloy, Cu, Au, and Ag.
Claim 5
Dependent Claim
18 words
The antifuse recited in claim 3 wherein said diffusion layer is TiN and said metal layer is Al.
Claim 6
Dependent Claim
122 words
An electrically programmable semiconductor antifuse comprising: a silicon substrate; a diode P-N junction formed in said silicon substrate; isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; a metal layer over said P-N junction, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said P-N junction; and programmable pulse generating means connected across said metal layer and said silicon substrate for stressing said P-N junction by a voltage pulse to produce a prescribed current density and creating a prescribed joule heating resulting in said silicide formation and penetration into said P-N junction to thereby program said antifuse to conduct at prescribed voltages.
Claim 7
Dependent Claim
122 words
An electrically programmable semiconductor antifuse comprising: a silicon substrate; a diode P-N junction formed in said silicon substrate; isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; a metal layer over said P-N junction, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said P-N junction; and programmable pulse generating means connected across said metal layer and said silicon substrate for stressing said P-N junction by a voltage pulse to produce a prescribed current density and creating a prescribed joule heating resulting in said silicide formation and penetration into said P-N junction to thereby program said antifuse to conduct at prescribed voltages.
Claim 8
Dependent Claim
26 words
The antifuse recited in claim 5 wherein said isolation means comprises a trench in said substrate surrounding said P-N junction and filled with SiO 2 .
Claim 9
Dependent Claim
27 words
The antifuse recited in claim 6 wherein said metal layer is composed of a metal chosen from the group consisting of Ti, Cr, W, Mo, and Ta.
Claim 10
Dependent Claim
11 words
The antifuse recited in claim 7 wherein said metal is Ti.
Claim 11
Dependent Claim
24 words
The antifuse recited in claim 8 further comprising a TiN diffusion barrier over said metal and an Al layer over said TiN diffusion barrier.
Claim 12
Dependent Claim
113 words
An electrically programmable semiconductor antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode P-N junction formed in said silicon substrate; c) isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; and d) a metal layer over said P-N junction, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said P-N junction when said antifuse is programmed, said metal layer being composed of a metal chosen from the group consisting of Ti, Cr, W, Mo, and Ta.
Claim 13
Dependent Claim
113 words
An electrically programmable semiconductor antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode P-N junction formed in said silicon substrate; c) isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; and d) a metal layer over said P-N junction, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said P-N junction when said antifuse is programmed, said metal layer being composed of a metal chosen from the group consisting of Ti, Cr, W, Mo, and Ta.
Claim 14
Dependent Claim
26 words
The antifuse recited in claim 10, wherein said isolation means comprises a trench in said substrate surrounding said P-N junction and filled with SiO 2 .
Claim 15
Dependent Claim
11 words
The antifuse recited in claim 10, wherein said metal is Ti.
Claim 16
Dependent Claim
25 words
The antifuse recited in claim 12, further comprising a TiN diffusion barrier over said metal layer and an Al layer over said TiN diffusion barrier.
Claim 17
Dependent Claim
107 words
An electrically programmable semiconductor antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode formed in said silicon substrate; c) isolation means for electrically and thermally isolating said diode in said silicon substrate, said diode being exposed through said isolation means; and d) a metal layer over said diode, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said diode when said antifuse is programmed, said metal layer being composed of a metal chosen from the group consisting of Ti, Cr, W, Mo, and Ta.
Claim 18
Dependent Claim
107 words
An electrically programmable semiconductor antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode formed in said silicon substrate; c) isolation means for electrically and thermally isolating said diode in said silicon substrate, said diode being exposed through said isolation means; and d) a metal layer over said diode, said metal layer for reacting with said silicon substrate to form a silicide penetrating into said diode when said antifuse is programmed, said metal layer being composed of a metal chosen from the group consisting of Ti, Cr, W, Mo, and Ta.
Claim 19
Dependent Claim
13 words
The antifuse recited in claim 14, wherein said diode comprises a Schottky diode.
Claim 20
Dependent Claim
13 words
The antifuse recited in claim 14, wherein said diode comprises a P-N junction.
Claim 21
Dependent Claim
108 words
An electrically programmable antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode P-N junction formed in said silicon substrate; c) isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; d) a metal diffusion barrier over said P-N junction; and e) a metal layer over said diffusion barrier, said metal layer for reacting i) with said diffusion barrier to penetrate therethrough and ii) with said silicon substrate to penetrate into said P-N junction, when said antifuse is programmed.
Claim 22
Dependent Claim
108 words
An electrically programmable antifuse programmable under prescribed joule heating programming conditions and which conducts at prescribed voltages when programmed, said antifuse comprising: a) a silicon substrate; b) a diode P-N junction formed in said silicon substrate; c) isolation means for electrically and thermally isolating said P-N junction in said silicon substrate, said P-N junction being exposed through said isolation means; d) a metal diffusion barrier over said P-N junction; and e) a metal layer over said diffusion barrier, said metal layer for reacting i) with said diffusion barrier to penetrate therethrough and ii) with said silicon substrate to penetrate into said P-N junction, when said antifuse is programmed.
Claim 23
Dependent Claim
26 words
The antifuse recited in claim 17, wherein said isolation means comprises a trench in said substrate surrounding said P-N junction and filled with SiO 2 .
Claim 24
Dependent Claim
49 words
The antifuse recited in claim 17, wherein said diffusion barrier is selected from the group consisting of TiN, W, Ti-W alloy, and layers of Ti and Cr, and said metal layer is composed of a metal selected from the group consisting of Al, Al-Cu alloy, Cu, Au, and Ag.
Claim 25
Dependent Claim
18 words
The antifuse recited in claim 19, wherein said diffusion barrier is TiN and said metal layer is Al.
References Cited (Backward Citations)
US4312046A
Cited
US4961102A
Cited
US4491857A
Cited
US4727409A
Cited
US4670970A
Cited
US4748490A
Cited
US4899205A
Cited
US4943538A
Cited
US4881114A
Cited
US4876220A
Cited
DE3927033A1
Cited
US4931353A
Cited
US5019878A
Cited
US4914055A
Cited
EP0452091A2
Cited
EP0452090A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-28 | 1997-09-27 | 1998-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-28 | 2001-09-27 | 2002-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-28 | 2005-09-27 | 2006-03-29 | $7700.00 | Window Closed / Lapsed |